The purpose of this Core is to insure high quality experimental preparations. We plan to use owl monkeys (Aotus trivirgatus) because the cortical visual areas have been extensively mapped in these animals (Allman et al., 1994). We have a colony of owl monkeys that produces 2 to 3 infants per year, which will be used in the developmental atlas project. Our attending veterinarian, Dr. Janet Baer, is an authority on the husbandry and diseases of owl monkeys and has published extensively on this subject (Baer, 1994). We also have a small colony of dwarf lemurs, which are advantageous for MRI imaging studies because of their small size. We plan to hire an animal technician who will assist in the anesthesia, physiological monitoring and recovery of the animals to be used in the imaging studies.